Christmas with the Joker is one of the most brilliant Christmas episodes in all of animation IMO, and one of the best Batman Christmas stories in general. It is all about both Batman and the Joker wanting to spend time with their families for Christmas. The scary thing? They both make each other's wishes come true.

To Batman, his family is Alfred and Robin. They want to spend Christmas with him, but Bruce is too fixated on stopping crime. The Joker essentially makes Bruce's Christmas happen by fulfilling Batman's wish...to stop crime (Joker's crime). After that, Bruce finally gets the time to celebrate Christmas with Alfred and Robin.

To the Joker, Batman is his "family". The Joker gets his Christmas wish come true by having Batman come out on Christmas Eve to not just stop him, but to spend time with him. Also notice how he says "Welcome to the first Joker Christmas special" in the episode. Yep, that's right. He plans on doing this every year....

It really is a brilliant episode. It not only explores the disturbing family relationship between Batman and the Joker, but also manages to stay in line with the very lighthearted and warm tone of Christmas.